I didn't initially invite put a plus-one for 2 cousins because they are not dating anyone, and they will know a bunch of people at my wedding. I now have room for them to bring a plus-one and the wedding invitations have gone out. What is the best way to let the cousins know they can now bring a plus-one without looking I breached etiquette?
TIA.
ETA: What I mean by "best way" is how to word the email/conversation.